Generators can be found on any vehicle since the advent of OBDII. Why? More reliable and cheaper.
Tester
My 2006 Toyota has OBDII and an alternator.
“Would like to know exactly what the part is inside the alternator which tell the ECM to accept the charge to the battery”
Probably a part of the voltage regulator circuit, which is built into the alternator.
http://www.autopartswarehouse.com/sku/Pontiac/G6/AC_Delco/Generator/2007/Base/AC25922329.html
Tester
Autopartswarehouse calls it a generator in my 97 Nissan truck, but I assure you that it is an alternator.
The term alternator is really a marketing term invented by Chrysler back in the early 60’s. It is a three phase generator with a built in rectifier. Three phase AC generators have been around since the days of Tesla and Westinghouse. It is the most efficient way of generating electricity.
It would not make sense to go back to the one phase DC generators of old. They are very inefficient and much heavier than the “alternator”. Technically an “alternator” is a generator.
Technology has come a long way from the day of old generators. Back then they would use round copper wire and do what is called “Mush Windings”. That meant the copper wire was wrapped randomly and thereby lot of copper wire was required to produce the voltage that was required. Also the more copper wire that was wrapped reduced the fluctuation of the output DC voltage. Todays generators now use what is called “Formed Windings”. Instead of using copper wire with a round cross section, the copper wire has a square cross section. Now the copper wire can be wrapped abutting each other and stacked atop each other. This then allows for the use of less copper wire to produce the voltage required reducing weight and also totally eliminates the fluctuation of the output of the generator. So now you have a lighter more efficient generator.
So now the automotive engineers figured that if the generator is producing a more stable/predictable voltage, the computer can be used as the voltage regulator. This eliminates the requirement for a separate stand alone voltage regulator.
A lot of manufacturers are moving away from alternators. And it’s the wave of the future.
Tester
The same techniques used in generators can also be used in alternators. Because the alternator generates in three phases, it will always be more efficient than a DC generator. The computer can still control the output voltage.
Many of the newest generators are known as smart alternators. It measures the temperature of the intake air to optimize the voltage for charging the battery. It is far better than the old built in regulators.
BTW, they don’t use copper anymore, they use a special alloy of aluminum.
True! But a generator doesn’t require rectifiers or diodes like an alternator does. And if a rectifier in an alternator fails the AC ripple voltage can confuse and/or damage computers/modules. And they’re not putting less of them in vehicles.
Tester
DC Generators have more ripple than an alternator. The amplitude of the ripple is a function of the number of coils used inside the generator. The coils in a DC generator are used only one at a time so that is the reason for their bulk. A three phase generator has three split coils and all are used all the time, although each coil produces about 90% of its power in two 120 degree arcs per cycle.
Generator DC ripple is reduced with form windings. A failed rectifier in an alternator produces AC ripple. Not good for computers or modules in a vehicle.
Tester
Form windings have nothing to do with ripple. They are more efficient, but a DC generator uses one or more windings with a split commutator. A single winding will produce an output with a lot of ripple, basically two 180 degree sine waves. Add more windings and you reduce the amplitude of the arcs, but only one winding is in the circuit at any time. A really big disadvantage to this is that all of the windings have to be rotor windings, the field winding is a single stator.
An “alternator” has one field winding that is the rotor with either three single or three split stator windings. All the windings are in use all the time.
In a generator, if the commutator develops a bad spot, which is more common than defective diodes in my experience, the ripple will greatly increase.
In checking several sources for replacement generator/alternators for this vehicle, several manufacturers are OEM. Those made by AC Delco are called generators, those made by Denso and others call them alternators.
Generator is the SAE J1930 term for alternator. All modern cars have alternators, however they have gone back to the term “generator”.
When Chrysler started calling them generators (again) about 10 years ago it was explained that although an alternator produces alternating current the output on the positive stud is direct current, thus it is defined as a generator.
The following is the charging system description for the G6;
GENERATOR
The generator features the following major components:
The delta stator
The rectifier bridge
The rotor with slip rings and brushes
A conventional pulley
Dual internal fans
The regulator
Very interesting discussion going on here. Just when I though this problem was licked the problem reappeared. No problems for about 100 miles then suddenly for a few seconds the “idiot light” for the charging system turned on and chimed then went off. This happened after being caught in a one hour traffic jam.
Got to my destination and plugged in my scangauge just as the “idiot light” lit and the chimer went off for the second time and to my surprise NO change in volts 13.8 ! Have a trip planned but now I hesitate to take this ride anywhere that might leave me stranded like it had done before.
Can this intermittent problem be a faulty ECM and if it is how can it be checked prior to replacing it with another? The pickle continues.
The old fashioned generators like the one in my 59 T-Bird barely keeps a charge on the battery at night with just the headlights on at idle… Voltage drops down to 12.8.
Bring it up to about 1500 RPM and will show 13.8. I remember my dads 53 chevy at night where he had an ammeter.
When he came to a stop it would show a slight discharge. I remember when we were stuck in a bad traffic jam due to an accident he turned the headlights off due to the discharge at idle.
My 67 chevy and 74 Nova did have an alternator, but had a "gen " light. All these so called new generators are alternators and have the diode packs etc.
The nice thing with the old time generators, they were easy to repair. Usually just needed new brushes and commutator cleaned. I bought the entire kit for my 59 which included 2 new bearings, brushes and cleaning paper for about 15.00.
Only problem was those things are heavy,
It took 2 of us to get it mounted again, one guy underneath the car and another pulling it up with a rope topside to get the bolts aligned .
gjd521, I think you may have a wiring problem between the computer and the generator/alternator. The voltage regulation is provided by the computer by varying the field current. That connection at either the computer end or the alternator end might have a problem. The problem could be in the crimp or the wire itself.
If this is a smart alternator, then there is an air temp sensor usually located in the duct from the air filter to the throttle body. If the sensor or it’s wiring has a defect, it could affect the field current as well.
FYI, the term “alternator” only applies to cars. In the power industry, they are referred to as poly phase generators.
Update # 17. Wiggled the plug that goes into the back of the alternator (2 wire plug) and the “idiot light” went off! Unable to replicate the off/on 100% but sometimes I can. So it’s either the plug or wires that run into the ECM.
My scangauge shows no dropping of voltage when the light appears but effectively shows a drop when I start the ride then jumps back to normal when the “idot light” turns off.
Either by me wiggling the wires I become a ground and the light goes off or that the “idiot light” flickers on even though normal voltage should tell it not to and I’m worrying about nothing but a light which is not giving me an accurate reading of the charging system.
My wiring schematic shows a 3-wire system with one wire going into a fusible link at the starter. I have just a grey and orange wire which goes into the back of the alternator.
The little metal tabs in the connector make contact with the alternator by spring tension.
Sometimes removal of each tab from the connector housing and a little careful bending with a stout sewing needle can tighten things back up.
Good job. Looks like you are on the right track.